Hydraulic jack.



5N0. 874,700. 7 PATENTEDDEC. 24, 1907.

1T. W. NELSON. I

HYDRAULIC JACK. APPLICATION FILED mm: 14. 1906. RENEWED 001'. 31, 1907.

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his fliiorneys 1105874300. I PATENTED DEC. 24', 1907.

L I -J. w. NELSON.

HYDRAULIC JACK.

APPLICATION IILED JUNE 14, 1906. RENEWED 001'. 31, 1907.

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JAMES W. NELSON, OF NEW YORK, N. Y:

HYDRAULIC JACK.

Specification of Letters Patent.

Patented. Dec. 24, 1902.

Application filed Julie 14, 1906I Serial No. 321.621. Renewed October31. 1907. Serial No. 400,071-

To all whom it may concern:

Be it known that I, JAMES W. NELsoN, a citizen of the United States, andresident of the city of New York, borough of Brooklyn, county of Kings,and State of New York, have invented. certain new and usefulImprovements in Hydraulic Jacks,- of which the following is aspecification.

This invention relates to hydraulic jacks,

and particularly todouble or multiple-pump jacks, wherein, through theemployment of all of the pumps, power is sacrificed for speed until theram has been raised to the point where it receives the full weight ofthe load,-

allel to each other, and has in view, in con nection with such a pump orplunger arrangement, a minimum number of valves, and a valve arrangementwhereby, withthe simplest possible mechanism, said valves will be undermanual control to render one or all thereof inoperative for the purposeshereinafter set forth. 1

My invention will be more readily under- -stood by reference to theaccompanying drawings, forming a part of this specification, and inwhich Figure 1 is a vertical, sectional, side elevation of a jackembodying my invention. Fig. 2 is a transverse section on an enlargedscale on the line 22 of Fig. 1. Figs. 3, 4, and 5 are vertical sectionson the lines 33, 4-4

.and 55, respectively, of Fig. 2.

I have selected for the purpose of illustration a general type ofhorizontal jack, comprising a heavy metal shell or casing 6 havingmounted in one side thereof a ram-cylinder 7 and in the other side apump-block 8 and the pump mechanism. This-shell or casing 6 may be ofany desired configuration, the ram-cylinder 7 being preferably screwedinto a suitable screw-threaded aperture and the bottom thereof fittingwithin a socket, as shown, and the pump-block 8 bein provided withscrew-threads at its upper en whereby it may be inserted in a suitablepocket theresnugly .known principles of hydraulics.

for and firmly held in place by means of. the threaded ring 9.

The shell or casing 6, therefore, as will be noted, provides a chamber.10 serving as both, a reservoir for the liquid employed and. for thepump operating mechanism. The latter comprises a shaft 11 extendingthrough chamber, with suitable bearings inthe walls thereof, andprovided on the outside of said chamber with a head 12 apertured for thereception of an ordinary pump handle lever (not shown) by means of whichsaid shaft may be rocked. A block 13 is vertically slidable in suitableguides 14 14, mounted within said chamber 10, and is provided with anopening or pocket for the reception of a knuckle 15 fixed upon saidshaft 11. It will be a arent that when said shaft is rocked the lil dck13 will-be vertically reciprocated.

The block 13 carries the downwardly projecting piston or plunger rods 16and 17 which extend into the corres onding pumpbores 18 and 19 in thepump lock 8. Each of the rods 16 and '17 is provided with a head oriston, 20 and 21, respectively, which fit in each of the pump bores 18,an 19, a tight 'oint being provided'by means of any well known method ofpacking. These bores are preferably of different d1- ameters, and'thepiston-heads 20 and 2-1 of correspondin diameters. In this type of jackthis di erence in diameter is not nec-.-

essary, as it is where the pistons are arranged end-to-end, or What maybe termed a tandem one piston pro'ectmg' from the end of the other. Itis we known the'object of a double-pump is to provldefor greater speedin raising the ram to where it receives the full wei ht of the. ad,

at which point one, prefera ly the larger,

pump is rendered inoperative in order to increase the power through adecrease in thearea of pressure surface under the w I therefore preferto have-the piston of what may be termed the real pressure pump ofcorn,- paratively small cross-sectional area, the other of larger areain order to accelerate as muchas possible the speed of the, ingrrampriorto its meetingthe load;

he pump bores 18 and 19 do not extend completely through the pump-block,but are permanently closed at the ottoms. Parallel thereto, andextending completely through the block 8, is the bore 22, which,

. Above the valve 28, a duct 30 connects the bore 22 with the chamber 31below the smaller iston. Above this duct 30, the bore 22 is furthercontracted to form a seat for the valve 32, the valve 28 being providedwith a stem 33 extending upward nearly but not quite to said valve 32.Above said valve 32, a duct 33 connects said bore 22 with the chamber 34below the other pump piston, and above this duct 33 said bore 22 isagain contracted to form a seat for the valve 35; the valve 32 beingsimilarly provided with a stem 36 extendupward nearly but not quite tosaid ive 35. The valve 33 is similarly provided with a stem 37 extendinginto the upper and preferably enlarged portion 38 of said bore 22.

The shell or casing 6 is provided with an a erture or openingimmediately above t e chamber 10, through which said chamber may befilled and which should be large enough to permit of the removal of thepistons and other parts for repacking, repair 7 or re lacement.Thisopening is preferably close by means of a screw cap 39, throughwhich extends a rod '40 which may be moved up or down through a-limiteddistance by being screw-threaded. into the said lcap, rotation of said.rod 40 being facilitated by means of a hand-wheel 41 or its e uivalent,secured to said rod on the outsi e of the shell or casing 6. This rodextends downwardly into the enlarged portion 38 of said bore 22 to apoint slightly above or just contacting with the stem 37 of the valve 35when the latter is in its seat.

Under normal conditions, when the block 13 is raised in the mannerhereinbefore indicated and therewith the pump pistons 20 and 21, aartial vacuum will be formed in each of t e um chambers 34 and 31. Thevacuum in t e chamber 34 will, on account of the greater pressure of theliquid in the reservoir 10, unseat the valve 35 and the liquid will beforced into the said chamber 34. Similarly, the vacuum in the chamber 31Will effect the unseating of the valve 32 and cause the liquid to fiowinto said chamber 31. Upon the downward stroke of said istons, thegreater pressure on the under si e of the valve 35 will seat the sameand the liquid in both of the chambers 34'and 31 be forced past thevalve 28 and through the ductfj26 into the ram chamber 24. In thismanner the ram may be rapidly raised to the point where it re ceivesthefull weight of the load. At this point, the-wheel 41 may be turned,forcing own the rod 40 until the valve 35 is unseated and held off itsseat. Thereafter all liquid which is drawn into the chamber 34, upontheup-stroke of the piston, will, upon the down-stroke thereof, be forcedbackinta the reservoir 10, while the'liquid which has been drawn intothe chamber 31, the valve 32 still being operative, will be forced asbefore into the ram chamber and under greater pressure.

After the desired work has been done, and it is desired to release theli uid in the ram chamber in order to lower t e ram or contract theparts for subsequent or following operation, the rod 40 is furtherdepressed, by means of the wheel 41, until first the valve 35 contactswith the stem 36 and unseats the valve 32, and second said valve 32 issufficiently depressed to engage the stem 33 and unseat the valve 28,thus' opening and holding open the entire passage from the ram chamber24 to the reservoir 10. The liquid in the ram chamber has thus free anduninterrupted passage from the ram chamber back to reservoir.

It will be apparent that while I have shown and described a jack inwhich the ram and ram chamber are located laterally of the pum block,the principles df my invention may e applied with equally satisfactoryresults to a construction of jack wherein the pump-block forms a part ofthe ram itself. Such construction would eliminate the necessity for alateral duct such as duct 26, the bore 22 leading directly into the ramchamber below the pum -block, for whichpurpose the plug 23 would besuitably apertured.

It will be furthermore apparent that while I have hereinbefore referredto the device illustrated and described as being of a horizontal ty c,it being, possibly, better adapted for emp oyment in a horizontaldirection than jacks in which the ram contains the pump-block andoperating mechanism, it is nevertheless true t at this type of jack maybe used vertically as well as horizontally and with equally effectiveresults. My invention is therefore not limited to the type of jack norto the specific construction herein shown and described.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:

1. In a hydraulic jack, a pump-block pro- .vided with a plurality ofparallel pump-bores to ram chamber separate from the pumpchambers butcommunicating therewith, valves in said passage, and means for holdingall of said valves off their seats.

3. In a hydraulic jack, a plurality of parallel pump-pistons, a seriesof check-valves to control the flow from reservoir -to ram chamber andmeans for positively unseating all of said valves by one operation.

4. In a hydraulic jack, the combination, with two parallel pumps, of aseries of valves for controlling flow from reservoir to ram chamber andthe first of which'checks back flow from one of said pumps only, andmeans for positively unseating said first valve, said means beingfurther operable to unseat'all of said valves.

5. In a hydraulic jack, the combination,

with two parallel pumps, of a pump-block having corresponding pump boresand a separate fluid-passage from reservoir. to ram chamber separatelycommunicating with each pump-chamber, an initial inlet valve to saidpassage, a final outlet valve therefrom, a valve intermediate of saidpump-chambers, and means for renderinginoperative said inlet valve onlyor all of said valves.

6. In a hydraulic jack, the combination, with two parallel and connectedpump pistons, of a pump block having corresponding pump bores and valvesfor said-two pump pistons in a single valve bore.

7. In a hydraulic jack, the combination, with two parallel and connectedpump pistons, of a pump block having corresponding pump bores andsuperposed valves for said two pump pistons contained in a single boreseparate from the pump bores but communicating therewith. v

In witness whereof, I have signed my name to the foregoing specificationin the presence of two subscribing witnesses.

JAMES W. NELSON.

Witnesses WM. W. RoBEnTs, J. C. CONRA

